Pharmaceutical compositions of lipase-containing products, in particular of pancreatin

ABSTRACT

Orally administrable pharmaceutical compositions of lipase-containing products, particularly pancreatin and pancreatin-containing products, or of enzyme products which contain at least one lipase of non-animal, especially microbial origin, which improve the lipolytic activity and particularly result in stabilization of the lipase in the acidic pH range. These oral pharmaceutical compositions contain a system which includes at least one surfactant and one co-surfactant and optionally a lipophilic phase, and are self-emulsifiable on contact with a hydrophilic and a lipophilic phase. The compositions according to the invention are suitable for treating or inhibiting maldigestion, especially maldigestion due to chronic exocrine pancreatic insufficiency, in mammals and humans.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. provisional patent application No. 60/554,993, filed Mar. 22, 2004, the entire disclosure of which is incorporated herein by reference. Convention priority is also claimed based on European patent application no. 04 10 1164.4, filed Mar. 22, 2004, the disclosure of which is likewise incorporated by reference herein.

BACKGROUND OF THE INVENTION

The invention relates to novel pharmaceutical compositions of lipase-containing products for oral administration, in particular pancreatin and pancreatin-containing products, or of enzyme products containing at least one lipase of non-animal, especially microbial origin, in which the pharmaceutical compositions provide improved lipolytic activity, in particular a stabilization of the lipase in the acidic pH range. These novel pharmaceutical compositions contain a system which comprises at least one surfactant and one co-surfactant, and are self-emulsifiable on contact with a hydrophilic and a lipophilic phase. The pharmaceutical compositions of the invention are well suited for the treatment and/or inhibition of maldigestion, in particular maldigestion based on chronic exocrine pancreatic insufficiency, in mammals and humans.

Maldigestion in mammals and humans is usually based on a deficiency of digestive enzymes, in particular on a deficiency of endogenous lipase, but also of protease and/or amylase. The cause of such a deficiency of digestive enzymes is frequently a hypofunction of the pancreas (=pancreatic insufficiency), the organ which produces the most, and the most important, endogenous digestive enzymes. If the pancreatic insufficiency is pathological, this may be congenital or acquired. Acquired chronic pancreatic insufficiency may, for example, be ascribed to alcoholism. Congenital pancreatic insufficiency may, for example, be ascribed to the congenital disease cystic fibrosis. Consequences of the deficiency of digestive enzymes may include severe symptoms of under-nutrition and malnutrition, which may be accompanied by increased susceptibility to secondary illnesses.

Substitution with similarly-acting exogenous digestive enzymes or mixtures of digestive enzymes has proved effective treatment for a deficiency in endogenous digestive enzymes. At present, pharmaceutical preparations (=preparations) which contain porcine pancreatin (=pancreatin) are frequently used for this purpose. Such mixtures of digestive enzymes obtained from the pig pancreas comprise lipases, amylases and proteases, and can be used effectively for enzyme substitution therapy in humans due to the great similarity of the enzymes and accompanying substances contained therein to the contents of human pancreatic juices. For example, processes are described in U.S. Pat. No. 4,019,958 (=DE 25 12 746) and German Patent Publication No. DE 42 03 315 by which pancreatin is obtained as a natural enzyme mixture by extraction from porcine pancreas and subsequently is converted in a known manner into the desired pharmaceutical form. The pancreatic enzymes are usually administered orally in the form of solid preparations. Pancreatin is thus commercially available, for example under the trade name Kreon®, in the form of granules, pellets or capsules with enteric-coated micropellets.

In order that, when taken orally, the administered enzyme mixtures are not irreversibly denatured in the stomach by gastric acid and proteolytic enzymes, such as pepsin present there, it is necessary to provide the enzyme mixtures with an enteric coating. Such a coating enables the enzyme mixtures to pass intact through the stomach to their point of action, the duodenum, where, due to the neutral to slightly alkaline conditions prevailing there, the protective layer is broken down and the enzymes are released. Like the endogenous pancreatic enzymes of healthy humans, the orally supplied enzymes can exert their enzymatic action, in particular amylolytic, lipolytic and proteolytic activity, there. Such solid pancreatin formulations which can be coated with an enteric film are described e.g. in U.S. Pat. No. 4,280,971 (=EP 21, 129).

U.S. Pat. No. 5,378,462 (=EP 583,726) describes pancreatin micropellet cores coatable with an enteric film having a pancreatin content of 65-85%, in particular 75-80%, by weight which have a bulk density of 0.6 g/ml to 0.85 g/ml, consisting essentially of pancreatin, polyethylene glycol 4000 and low-viscosity paraffin, containing per 100 parts by weight pancreatin: 15-50, in particular 20-30, parts by weight polyethylene glycol 4000; and 1.5-5, in particular 2-3, parts by weight low-viscosity paraffin, and having a spherical to ellipsoid form, the sphere diameter or the minor axis being in the range of 0.7-1.4 mm, in particular 0.8-1.2 mm, and having a particle-size distribution in which at least 80% of the pancreatin micropellet cores have a ratio of minor axis to major axis in the range of 1:1 to 1:2.

Furthermore, U.S. Pat. No. 5,993,806 (=EP 826,375) describes the use of lecithin as a stabilizing agent added to water-soluble pharmaceutical preparations of mixtures of digestive enzymes which contain protease/lipase mixtures, in particular pancreatin, and which are suitable for the preparation of aqueous solutions for continuous introduction into the gastrointestinal tract via probes. The lecithin is added to stabilize the mixtures of digestive enzymes against a decrease in the lipolytic activity under the influence of moisture.

In the case of pharmaceutical formulations not coated with enteric films, it is known that at the point of action of the enzymes, in the duodenum, often only a very small proportion of the lipase contained in the pharmaceutical preparation and taken therewith is active. Thus in German Patent Publication No. DE 36 42 853 such enzyme deactivation is ascribed to insufficient neutralization of the gastric acid in the duodenum. Whereas in a healthy human the postprandial intraduodenal pH value is about 6, patients with pancreatic insufficiency only have a pH value of about 4. At this pH value, the lipase contained in the pharmaceutical preparation has only one fifth of the activity that it would otherwise have at a pH value of 6.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide pharmaceutical compositions which contain enzymes or enzyme mixtures with at least lipolytic activity and have improved lipolytic activity and in particular show a stabilization of the lipase activity in the acidic pH range.

According to the invention, pharmaceutical compositions intended for oral administration are provided which comprise enzymes or enzyme mixtures with at least lipolytic activity and a system comprising at least one surfactant and at least one co-surfactant. The pharmaceutical compositions of the invention are characterized in that they form emulsions upon contact with a hydrophilic phase and a lipophilic phase. Preferably the hydrophilic phase used to form the final emulsion after ingestion of the pharmaceutical composition is supplied by the physiological fluid of the digestive milieu. In a further embodiment of the present invention, the lipophilic phase used to form the final emulsion in the digestive tract after ingestion of the pharmaceutical composition is at least partially supplied by the lipids present in the food ingested. In particular, to achieve this object the invention provides pharmaceutical compositions which contain systems which comprise at least one surfactant, one co-surfactant and a lipophilic phase.

Surprisingly, a lipase-containing pharmaceutical composition containing such a system has improved lipolytic activity and a lipolytic activity which is stabilized in the acidic pH range. The use of such a system in pharmaceutical compositions of enzymes or enzyme mixtures with at least lipolytic activity furthermore has the advantage that pharmaceutical compositions containing such enzymes or enzyme mixtures can also be used without enteric coatings, such as are described for example in U.S. Pat. No. 5,378,462. In the pharmaceutical compositions according to the invention the reduction in the lipolytic activity during passage through the stomach is very much less than with pharmaceutical compositions prepared without the aforementioned system. The system consisting of surfactant, co-surfactant and optionally a lipophilic phase, stabilizes the lipolytic activity of the pharmaceutical compositions according to the invention in the acidic pH range of the stomach compared with conventional formulations.

The fact that the use of such enteric-coated polymer films and softeners which are otherwise necessary for film-coating various medicament forms (granules, pellets, mini-tablets, tablets etc.) can be omitted in the preparation of the lipase-containing compositions according to the invention yields further advantages. Thus the safety profile of the pharmaceutical composition is improved by omitting the enteric polymer films and softeners, since unnecessary taking thereof is avoided. Furthermore, the proportions of the amount of film-coating material in the medicament forms provided with an enteric film is approx. 20-30% of the entire weight of the medicament form. The ability to omit these additives makes the amount of pharmaceutical composition to be taken smaller, which results in better acceptance by patients.

The possibility of omitting enteric coating of the enzymes or enzyme mixtures furthermore has the advantage that thorough mixing of the pharmaceutical preparation with the chyme can take place as early as in the stomach. Thereupon, there forms an emulsion or micro-emulsion with enlarged surface, on which the lipase contained in the pharmaceutical composition is distributed such that it is given optimum possibilities for attack for breaking down the triglycerides found in the chyme. The formation of emulsion and microemulsion is further intensified by the lipolytic breakdown of the triglycerides to form di- and monoglycerides and free fatty acids. The improved possibilities of attack for the lipase thus result in intensified breakdown of the triglycerides. The higher concentration of free fatty acids resulting from the food provided in this way results in better fat absorption in the duodenum. In vitro, an increase in the lipolytic activity by about 10% compared with conventional lipase-containing pharmaceutical preparations was determined for the pharmaceutical composition according to the invention. The pharmaceutical compositions according to the invention thus exhibit stabilization of the lipolytic activity in the stomach as well as in the duodenum. Additionally, due to the intensified formation of a (micro)emulsion, the lipolytic activity is increased. The (micro)emulsion already produced independently in the stomach results in better activation of the lipase contained in the pharmaceutical composition.

Self-emulsifying pharmaceutical compositions in general are already known from the prior art. Thus, for example, U.S. Pat. No. 6,054,136 (=EP 670,715) describes a perorally administered composition which is suitable for forming a microemulsion in situ with the biological liquid of the organism and thus is said to improve the biological availability of an active substance. Such pharmaceutical compositions are known under the term SMEDDS® (Self Microemulsifying Drug Delivery System) and consist in principle of a mixture of one or more active substances with a defined lipophilic phase, a defined surfactant and a defined co-surfactant, the properties of which are specified such that the end product is capable of forming a microemulsion on contact with a given volume of physiological liquid.

Furthermore, US 2003/021844 (=EP 1,058,540) describes what is called a SMEDDS® formulation in a particular pharmaceutical form, which is referred to as “pellet”. These pellets are composed of an active substance, in particular indomethacin, a binding agent which is suitable for improving the biological availability of the active substance, for example Gelucire® 44/14, and a diluent, for example lactose, in micronized form.

The object of prior art systems which automatically form a microemulsion was, however, always to increase the bioavailability of mostly lipophilic active substances in that the SMEDDS® formulation, as a result of the micelle formation, permits better absorption of the active substance through the duodenal wall into the blood circulation. In contrast, the aim of the present invention is to provide a pharmaceutical composition which does not contain any lipophilic active substances to be absorbed into the bloodstream, but which provides as active agent enzymes or enzyme mixtures with at least lipolytic activity which develop their action in the gastrointestinal tract. The self-emulsifiable pharmaceutical compositions according to the invention result in a surprising increase of the lipolytic activity contained therein and in an improved stability of the lipase in the acidic pH range. Such pharmaceutical compositions of lipase-containing enzyme products which are self-emulsifiable on contact with a hydrophilic phase and which comprise a system consisting of a surfactant, a co-surfactant and optionally a lipophilic phase have not been described in the prior art.

Subramanian and Wasan describe an assay in which they demonstrate that the substance Gelucire® 44/14 in vitro has an inhibiting effect on the pancreatic lipase activity [Subramanian R. & Wasan K. M. (2003) “Effect of lipid excipients on in vitro pancreatic lipase activity” Drug Dev. Ind. Pharm. 29(8): 885-90]. In this experiment, a particular lipid-containing assay buffer with separate solutions of Gelucire® 44/14, pancreatic lipase and co-lipase is mixed, and the influence of Gelucire® on the lipase activity is measured. Since the lipase activity decreases, the authors conclude that Gelucire® and similar lipidic additions to pharmaceutical formulations can have an adverse effect on the in vitro activity of the pancreatic lipase. In contrast, the present invention shows that self-emulsifiable pharmaceutical compositions consisting of lipase-containing enzyme mixtures and a system such as for example Gelucire® 44/14 result in an increase in the lipolytic activity contained in the pharmaceutical formulation.

Some expressions as used in the context of the present invention are explained in more detail below.

The “hydrophilic-lipophilic balance” (=HLB) value is an empirical parameter commonly used to characterize the relative hydrophilicity and lipophilicity of non-ionic amphiphilic compounds. Surfactants or co-surfactants with lower HLB values are more lipophilic and have greater solubility in oils, whereas surfactants or co-surfactants with higher HLB values are more hydrophilic and have greater solubility in aqueous solutions. It should be kept in mind that for anionic, cationic, or zwitterionic compounds the HLB scale is not generally applicable.

Generally, the HLB value of a surfactant or co-surfactant is a practical guide used to enable formulation of industrial, pharmaceutical and cosmetic emulsions. However, for many important surfactants, including several polyethoxylated surfactants, it has been reported that HLB values can differ by as much as about 8 HLB units depending upon the empirical method chosen to determine the HLB value [Schott, J. Pharm. Sciences, 79(1), 87-88 (1990)]. Likewise, for certain polypropylene oxide containing block copolymers (poloxamers), the HLB values may not accurately reflect the true physical/chemical nature of the compounds. Finally, commercial surfactant and/or co-surfactant products are generally not pure compounds, but are often complex mixtures of compounds, and the HLB value reported for a particular compound may more accurately be characteristic of the commercial product of which the compound is a major component. Different commercial products having the same primary surfactant and/or co-surfactant component can, and typically do, have different HLB values. In addition, a certain amount of lot-to-lot variability is expected even for a single commercial surfactant and/or co-surfactant product.

A “surfactant” in the context of the present invention is a chemical compound comprising two groups, the first being hydrophilic and/or polar or ionic and having a high affinity for water, and the second containing an aliphatic chain of greater or lesser length and being hydrophobic (lipophilic); i.e., a surfactant compound must be amphiphilic. These chemical compounds are intended to cause the formation and stabilization of oil-in-water emulsions. Surfactants with lower HLB values are more lipophilic and have greater solubility in oils, whereas surfactants with higher HLB values are more hydrophilic and have greater solubility in aqueous solutions. Suitable surfactants in the context of the present invention have an HLB value above 6 and below 18, preferably above 8 and below 16. Surfactants can be any surfactant suitable for use in pharmaceutical compositions. Suitable surfactants can be anionic, cationic, zwitterionic or non-ionic. Such surfactants can be grouped into some general chemical classes as explained below. It should be emphasized that the invention is not limited to the surfactants indicated herein, which show representative, but not exclusive, lists of available surfactants.

“PEG-Fatty Acid Monoester Surfactants”: Although polyethylene glycol (PEG) itself does not function as a surfactant, a variety of PEG-fatty acid esters have useful surfactant properties. Particularly preferred are PEG-fatty acid monoesters with aliphatic C₆-C₂₂ carboxylic acids, in which the polyethylene glycol comprises 6 to 60 ethylene oxide units per molecule. Examples of commercially available polyethoxylated fatty acid monoester surfactants include: PEG-4 laurate, PEG-4 oleate, PEG-4 stearate, PEG-5 stearate, PEG-5 oleate, PEG-6 oleate, PEG-7 oleate, PEG-6 laurate, PEG-7 laurate, PEG-6 stearate, PEG-8 laurate, PEG-8 oleate, PEG-8 stearate, PEG-9 oleate, PEG-9 stearate, PEG-10 laurate, PEG-10 oleate, PEG-10 stearate, PEG-12 laurate, PEG-12 oleate, PEG-12 ricinoleate, PEG-12 stearate, PEG-15 stearate, PEG-15 oleate, PEG-20 laurate, PEG-20 oleate, PEG-20 stearate, PEG-25 stearate, PEG-32 laurate, PEG-32 oleate, PEG-32 stearate, PEG-30 stearate, PEG 4-100 monolaurate, PEG 4-100 monooleate, and PEG 4-100 monostearate.

“PEG-Fatty Acid Diester Surfactants”: Polyethylene glycol (PEG) fatty acid diesters are also suitable for use as surfactants in the compositions of the present invention. Particularly preferred are PEG-fatty acid diesters with aliphatic C₆-C₂₂ carboxylic acids in which the polyethylene glycol comprises 6 to 60 ethylene oxide units per molecule. Representative commercially available PEG-fatty acid diesters include: PEG-4 dilaurate, PEG-4 dioleate, PEG-6 dilaurate, PEG-6 dioleate, PEG-6 distearate, PEG-8 dilaurate, PEG-8 dioleate, PEG-8 distearate, PEG-10 dipalmitate, PEG-12 dilaurate, PEG-12 distearate, PEG-12 dioleate, PEG-20 dilaurate, PEG-20 dioleate, PEG-20 distearate, PEG-32 dilaurate, PEG-32 dioleate, and PEG-32 distearate.

“PEG-Fatty Acid Mono- and Di-ester Mixtures”: In general, mixtures of surfactants are also useful in the present invention, including mixtures of two or more commercial surfactant products. Particularly preferred are mixtures of PEG-fatty acid mono- and diesters with aliphatic C₆-C₂₂ carboxylic acids in which the polyethylene glycol comprises 6 to 60 ethylene oxide units per molecule. Several PEG-fatty acid esters are marketed commercially as mixtures or mono- and diesters. Representative commercially available surfactant mixtures include: PEG 4-150 mono, dilaurate; PEG 4-150 mono, dioleate; and PEG 4-150 mono, distearate.

“Polyethylene Glycol (PEG) Glycerol Fatty Acid Esters”: In addition, PEG glycerol fatty acid esters suitable as surfactants in the context of the present invention include: PEG-20 glyceryl laurate, PEG-30 glyceryl laurate, PEG-15 glyceryl laurate, PEG-40 glyceryl laurate, PEG-20 glyceryl stearate, PEG-20 glyceryl oleate, and PEG-30 glyceryl oleate. Particularly preferred are PEG glycerol fatty acid esters with aliphatic C₆-C₂₂ carboxylic acids in which the polyethylene glycol comprises 6 to 60 ethylene oxide units per molecule.

“Polyethylene Glycol (PEG) Alkyl Ethers (mono- and/or diethers of polyethylene glycol)”: Ethers of polyethylene glycol and alkyl alcohols also are suitable surfactants for use in the present invention. Particularly preferred are PEG-fatty acid mono- and/or diethers with aliphatic C₁₂-C₁₈ alcohols in which the polyethylene glycol comprises 6 to 60 ethylene oxide units per molecule. Some commercially available examples of these surfactants include: PEG-2 oleyl ether (oleth-2), PEG-3 oleyl ether (oleth-3), PEG-5 oleyl ether (oleth-5), PEG-10 oleyl ether (oleth-10), PEG-20 oleyl ether (oleth-20), PEG-4 lauryl ether (laureth-4), PEG-9 lauryl ether, PEG-23 lauryl ether (laureth-23), PEG-2 cetyl ether, PEG-10 cetyl ether, PEG-20 cetyl ether, PEG-2 stearyl ether, PEG-10 stearyl ether, and PEG-20 stearyl ether.

“Polyethylene Glycol Sterol Ethers”: PEG-derivatives of sterols are suitable surfactants for use in the present invention. Examples of surfactants of this class include: PEG-24 cholesterol ether, PEG-30 cholestanol, PEG-25 phytosterol, PEG-5 soya sterol, PEG-10 soya sterol, PEG-20 soya sterol, and PEG-30 soya sterol.

“Polyethylene Glycol Sorbitan Fatty Acid Esters”: A variety of PEG-sorbitan fatty acid esters are available and are suitable for use as surfactants in the present invention. Examples of these surfactants include: PEG-10 sorbitan laurate, PEG-20 sorbitan monolaurate, PEG-4 sorbitan monolaurate, PEG-80 sorbitan monolaurate, PEG-6 sorbitan monolaurate, PEG-20 sorbitan monopalmitate, PEG-20 sorbitan monostearate, PEG-4 sorbitan monostearate, PEG-8 sorbitan monostearate, PEG-6 sorbitan monostearate, PEG-20 sorbitan tristearate, PEG-60 sorbitan tetrastearate, PEG-5 sorbitan monooleate, PEG-6 sorbitan monooleate, PEG-20 sorbitan monooleate, PEG-40 sorbitan oleate, PEG-20 sorbitan trioleate, PEG-6 sorbitan tetraoleate, PEG-30 sorbitan tetraoleate, PEG-40 sorbitan tetraoleate, PEG-20 sorbitan monoisostearate, and PEG sorbitol hexaoleate.

“Sugar Esters”: Esters of sugars, in particular mono-esters are suitable surfactants for use in the present invention. Examples of such surfactants include: sucrose distearate/monostearate, sucrose dipalmitate, sucrose monostearate, sucrose monopalmitate, sucrose monolaurate, and saccharose monolaurate.

“Polyoxyethylene-Polyoxypropylene Block Copolymers”: The POE-POP block copolymers are a unique class of polymeric surfactants. The unique structure of the surfactants, with hydrophilic POE and lipophilic POP moieties in well-defined ratios and positions, provides a wide variety of surfactants suitable for use in the present invention. The generic term for these polymers is “poloxamer” (CAS 9003-11-6). These polymers have the formula: HO(C₂H₄O)_(a)(C₃H₆O)_(b)(C₂H₄O)_(a)H, where “a” and “b” denote the number of polyoxyethylene and polyoxypropylene units, respectively.

Furthermore, “amphoteric compounds” such as fatty acid-amidoalkyl betaines with C₂-C₂₂ fatty acids are suitable surfactants.

The surfactant can also be, or include as a component, an “ionic surfactant,” including cationic, anionic and zwitterionic surfactants. Preferred anionic surfactants include fatty acid salts and bile salts. Preferred cationic surfactants include carnitines. Specifically, preferred ionic surfactants include sodium oleate, sodium lauryl sulfate, sodium lauryl sarcosinate, sodium dioctyl sulfosuccinate, sodium cholate, sodium taurocholate; lauroyl carnitine; palmitoyl carnitine; myristoyl carnitine, alginate salts; propylene glycol alginate; lecithins and hydrogenated lecithins; lysolecithin and hydrogenated lysolecithins; lysophospholipids and derivatives thereof; phospholipids and derivatives thereof; salts of alkylsulfates; sodium docusate; carnitines; and mixtures thereof.

More specifically, examples of preferred ionic surfactants include lecithin, lysolecithin, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, phosphatidylserine, lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylglycerol, lysophosphatidylinositol, lysophosphatidic acid, lysophosphatidylserine, PEG-phosphatidylethanolamine, PVP-phosphatidylethanolamine, stearoyl-2-lactylate, stearoyl lactylate, cholate, taurocholate, glycocholate, deoxycholate, taurodeoxycholate, chenodeoxycholate, glycodeoxycholate, glycochenodeoxycholate, taurochenodeoxycholate, ursodeoxycholate, tauroursodeoxycholate, glycoursodeoxycholate, cholylsarcosine, N-methyl taurocholate, caproate, caprylate, caprate, laurate, myristate, palmitate, oleate, ricinoleate, linoleate, linolenate, stearate, lauryl sulfate, teracecyl sulfate, docusate, lauroyl carnitines, palmitoyl carnitines, myristoyl carnitines, and salts and mixtures thereof.

A “co-surfactant,” sometimes also referred to as a “co-emulsifier”, in the context of the present invention is a chemical compound which has both hydrophobic (lipophilic) and hydrophilic portions, but with the hydrophobic (lipophilic) nature predominating. It is intended to make the aqueous and oily phases in a microemulsion mutually soluble. Suitable co-surfactants in the context of the present invention have an HLB value below 10, preferably below 8 and even more preferably below 6. Co-surfactants can be any partial esters and/or partial ethers of polyhydric (polyvalent) alcohols, such as glycerol, propylenglycol (1,2-propanediol; 1,2-dihdroxypropane), ethyl-diglycol or even polyglycerols (such as diglycerol, triglycerol, tetraglycerol etc.) with aliphatic carboxylic acids (fatty acids) or aliphatic alcohols (fatty alcohols).

Further co-surfactants, which can be grouped into some general chemical classes, are given below. It should be emphasized that the invention is not limited to the co-surfactants mentioned herein, which show representative, but not exclusive, lists of available co-surfactants.

“Mono-glycerides”: A particularly important class of co-surfactants is the class of mono-glycerides which are generally lipophilic. Particularly preferred are mixtures of monoglycerides with aliphatic C₆-C₂₂ carboxylic acids. Examples of this class of co-surfactants include: monopalmitolein (C16:1), monoelaidin (C18:1), monocaproin (C6), monocaprylin, monocaprin, monolaurin, glyceryl monomyristate (C14), glyceryl monooleate (C18:1), glyceryl monooleate, glyceryl monolinoleate, glyceryl ricinoleate, glyceryl monolaurate, glyceryl monopalmitate, glyceryl monostearate, glyceryl monopalmate, glycerol monostearate, glyceryl caprylate, and glyceryl caprate as well as mixtures thereof.

“Polyglycerized Fatty Acids”: Polyglycerol esters of fatty acids, in particular Polyglycerol mono-esters, are also suitable co-surfactants for the present invention. Particularly preferred are mixtures of polyglycerol esters with aliphatic C₆-C₂₂ carboxylic acids. Examples of suitable commercially available polyglyceryl esters include: polyglyceryl-2 stearate, polyglyceryl-2 oleate, polyglyceryl-2 isostearate, polyglyceryl-3 oleate, polyglyceryl-4 oleate, polyglyceryl-4 stearate, polyglyceryl-6 oleate, polyglyceryl-2 dioleate and polyglyceryl-6 dioleate.

“Propylene Glycol Fatty Acid Esters”: Partial esters of propylene glycol and fatty acids, in particular mono-esters, are suitable co-surfactants for use in the present invention. Particularly preferred are mixtures of propylene glycol esters with aliphatic C₆-C₂₂ carboxylic acids. Examples of co-surfactants of this class include: propylene glycol monocaprylate, propylene glycol monolaurate, propylene glycol oleate, propylene glycol myristate, propylene glycol monostearate, propylene glycol hydroxy stearate, propylene glycol ricinoleate, propylene glycol isostearate, propylene glycol monooleate, propylene glycol dicaprylate/dicaprate, propylene glycol dioctanoate, propylene glycol caprylate/caprate, propylene glycol dilaurate, propylene glycol distearate, propylene glycol dicaprylate, and propylene glycol dicaprate.

A “lipophilic phase” in the context of the present invention is understood to mean a water-immiscible liquid. The lipophilic phase may also be referred to as a lipidic phase. For compositions of the present invention in which the system also includes a lipophilic component, the lipophilic component is preferably a triglyceride or a mixture of a triglyceride and a diglyceride. Suitable lipophilic phases are preferably di- and triacylglycerides of aliphatic carboxylic acids (fatty acids) with 4 to 22 carbon atoms, in particular with 6 to 22 carbon atoms, and also mixtures thereof.

Preferred “di-glycerides” in the context of the present invention are mixtures of diglycerides with aliphatic C₆-C₂₂ carboxylic acids. Examples include: glyceryl dioleate, glyceryl dipalmitate, glyceryl dilaurate, glyceryl dilinoieate, glyceryl dicaprylate, glyceryl dicaprate, glyceryl caprylate/caprate, glyceryl distearate, glyceryl stearate/palmitate, glyceryl oleate/linoleate and glyceryl dimyristate.

Preferred “triglycerides” are those which solidify at ambient room temperature, with or without addition of appropriate additives, or those which in combination with particular surfactants and/or co-surfactants and/or active ingredients solidify at room temperature. Examples of triglycerides suitable for use in the present invention include: aceituno oil, almond oil, araehis oil, babassu oil, beeswax, black currant seed oil, borage oil, buffalo ground oil, candlenut oil, canola oil, castor oil, Chinese vegetable tallow oil, cocoa butter, coconut oil, coffee seed oil, corn oil, cottonseed oil, crambe oil, cuphea species oil, evening primrose oil, grapeseed oil, groundnut oil, hemp seed oil, illipe butter, kapok seed oil, linseed oil, menhaden oil, mowrah butter, mustard seed oil, oiticica oil, olive oil, palm oil, palm kernel oil, peanut oil, poppy seed oil, rapeseed oil, rice bran oil, safflower oil, sal fat, sesame oil, shark liver oil, shea nut oil, soybean oil, stillingia oil, sunflower oil, tall oil, tea seed oil, tobacco seed oil, tung oil (China wood oil), ucuhuba, vernonia oil, wheat germ oil, hydrogenated castor oil, hydrogenated coconut oil, hydrogenated cottonseed oil, hydrogenated palm oil, hydrogenated soybean oil, hydrogenated vegetable oil, hydrogenated cottonseed and castor oil, partially hydrogenated soybean oil, partially hydrogenated soy and cottonseed oil, glyceryl mono-, di-, tri-behenate, glycerol tributyrate, glyceryl tricaproate, glyceryl tricaprylate, glyceryl tricaprate, glyceryl triundecanoate, glyceryl trilaurate, glyceryl trimyristate, glyceryl tripalmitate, glyceryl tristearate, glyceryl triarchidate, glyceryl trimyristoleate, glyceryl tripalmitoleate, glyceryl trioleate, glyceryl trilinoleate, glyceryl trilinolenate, glyceryl tricaprylate/caprate, glyceryl tricaprylate/caprate/laurate, glyceryl tricaprylate/caprate/linoleate, glyceryl tricaprylate/caprate/stearate, glyceryl tricaprylate/laurate/stearate, glyceryl 1,2-caprylate-3-linoleate, glyceryl 1,2-caprate-3-stearate, glyceryl 1,2-laurate-3-myristate, glyceryl 1,2-myristate-3-laurate, glyceryl 1,3-palmitate-2-butyrate, glyceryl 1,3-stearate-2-caprate, glyceryl 1,2-linoleate-3-caprylate.

Fractionated triglycerides, modified triglycerides, synthetic triglycerides, and mixtures of triglycerides are also within the scope of the invention. Preferred triglycerides include vegetable oils, fish oils, animal fats, hydrogenated vegetable oils, partially hydrogenated vegetable oils, medium and long-chain triglycerides, and structured triglycerides.

Furthermore, the following compounds may be suitable as “lipophilic phase”: low-viscosity and high-viscosity aliphatic hydrocarbons, and also in particular oleic acid oleyl ester, isooctyl stearate, lauric acid hexyl ester, di-n-butyl adipate, isopropyl myristate, isopropyl palmitate and isopropyl stearate, oleyl alcohol, ethereal oils, isopropyl caprylate, isopropyl caprinate and isopropyl laurate.

“Complete Systems Composed of Surfactant, Co-Surfactant and Lipophilic Phase”

Several commercial surfactant and/or co-surfactant compositions contain small to moderate amounts of di- and triglycerides, typically as a result of incomplete reaction of a triglyceride starting material in, for example, a transesterification reaction. Such commercial surfactant and/or co-surfactant compositions, while nominally referred to as “surfactants” and/or “co-surfactant”, may be suitable to provide—in addition to the surfactant and/or co-surfactant part of the system—all or part of the lipophilic component, i.e. the di- and triglyceride component, for the compositions of the present invention.

Still other commercial surfactant and/or co-surfactant compositions having significant di- and triglyceride content are known to those skilled in the art. It should be appreciated that such compositions, which contain di- and triglycerides as well as surfactants and/or co-surfactants, may be suitable to provide the complete system composed of surfactant, co-surfactant and lipophilic phase, of the compositions of the present invention. Typical examples for such kind of systems are so-called macrogolglycerides (or polyoxyethylated glycerides) with different kinds of fatty acids. Macrogolglycerides are mixtures of mono-esters, di-esters and tri-esters of glycerol and mono-ester and di-ester of PEG (=polyethylene glycol, macrogol, polyoxyethlene, polyethylene oxide, polyglycol) with fatty acids, whereby the molecular mass of the PEG may be defined as well as the nature of the fatty acids. Macrogolglycerides can be obtained by a partial hydrolyzis/esterification reaction of triglycerides using the respective macrogol. Alternatively, macrogolglycerides can be obtained by esterification of glycerol and the macrogol and the corresponding free fatty acids. As triglycerides a variety of natural and/or hydrogenated oils can be used. Most commonly used oils are castor oil or hydrogenated castor oil or an edible vegetable oil such as corn oil, olive oil, peanut oil, palm kernel oil, apricot kernel oil, or almond oil, or the corresponding hydrogenated vegetable oil.

Typically, such transesterification products of oils and polyethylenglycol (or other polyalcohols) are named by there educts: PEG-20 castor oil, PEG-23 castor oil, PEG-30 castor oil, PEG-35 castor oil, PEG-38 castor oil, PEG-40 castor oil, PEG-50 castor oil, PEG-56 castor oil, PEG-7 hydrogenated castor oil, PEG-10 hydrogenated castor oil, PEG-20 hydrogenated castor oil, PEG-25 hydrogenated castor oil, PEG-30 hydrogenated castor oil, PEG-40 hydrogenated castor oil, PEG-45 hydrogenated castor oil, PEG-50 hydrogenated castor oil, PEG-60 hydrogenated castor oil, PEG-80 hydrogenated castor oil, PEG-8 corn oil, PEG-20 corn oil, PEG-20 almond oil, PEG-25 trioleate, PEG-40 palm kernel oil, PEG-60 corn oil, PEG-60 almond oil, PEG-8 caprylic/capric glycerides, lauroyl macrogol-32 glyceride (=PEG-32 hydrogenated palm kernel oil, e.g. Gelucire® 44/14), stearoyl macrogol glyceride (e.g. Gelucire® 50/13)

Examples of commercial co-surfactant compositions of mono-glycerides, in addition containing di- and triglycerides include some members of the co-surfactant families Maisines® (Gattefosse) and Imwitors® (Hüls). These commercial compositions may be used for providing the co-surfactant and the lipophilic phase in one composition. Specific examples of these compositions are: Maisine® 35-I (linoleic glycerides) and Imwitor® 742 (caprylic/capric glycerides).

“Aliphatic carboxylic acids with 6 to 22 carbon atoms”: In the context of the present invention, aliphatic carboxylic acids with 6 to 22 carbon atoms are understood to be aliphatic C₆-C₂₂ carboxylic acids. Thus preferably carboxylic acids selected from ‘the group containing caproic acid (C6), caprylic acid (C8), capric acid (C10), lauric acid (C12), myristic acid (C14), palmitic acid (C16), stearic acid (C18), arachidic acid (C20), and behenic acid (C22), as well as the corresponding unsaturated carboxylic acids, such as palmitoleic acid (C16), oleic acid (C18), linoleic acid (C18), linolenic acid (C18), eicosenoic acid (C20), individually or as a mixture, are used. Particularly preferably, the saturated carboxylic acids are selected.

“Aliphatic alcohols with 12 to 18 carbon atoms”: In the context of the present invention, aliphatic alcohols with 12 to 18 carbon atoms are understood to be aliphatic C₁₂-C₁₈ alcohols. Preferably alcohols selected from the group consisting of lauryl alcohol (C12), myristyl alcohol (C14), cetyl alcohol (C16), stearyl alcohol (C18), oleyl alcohol (C18), linoleyl alcohol (C18) and linolenyl alcohol (C18), individually or as a mixture, are used. Particularly preferably, the saturated alcohols are selected.

“Aliphatic alcohols with 12 to 22 carbon atoms”: In the context of the present invention, aliphatic alcohols with 12 to 22 carbon atoms are understood to be aliphatic C₁₂-C₂₂ alcohols. Preferably alcohols selected from the group consisting of lauryl alcohol (C12), myristyl alcohol (C14), cetyl alcohol (C16), stearyl alcohol (C18), arachidyl alcohol (C20), behenyl alcohol (C22), oleyl alcohol (C18), linoleyl alcohol (C18) and linolenyl alcohol (C18), individually or as a mixture, are used. Particularly preferably, the saturated alcohols are selected.

The “hydrophilic phase” in the context of the present invention is understood in particular to mean an aqueous phase which is preferably supplied by the physiological liquid of the digestion medium and/or by an aqueous liquid ingested in parallel with the food and/or the pharmaceutical preparation.

“Enzymes or enzyme mixtures with at least lipolytic activity” in the context of the present invention are understood to mean physiologically acceptable enzyme mixtures which contain at least one lipase. The enzymes or enzyme mixtures may, however, also have proteolytic activity in addition to the lipolytic activity, i.e. contain at least one protease, and/or amylolytic activity, i.e. contain at least one amylase.

Enzymes or enzyme mixtures may be used which exhibit (i) purely lipolytic; or (ii) lipolytic and proteolytic; or (iii) lipolytic and amylolytic; or (iv) lipolytic, proteolytic and amylolytic activity. Suitable enzymes or enzyme mixtures may be of any animal or microbiological origin. The enzyme mixtures with at least lipolytic, and optionally also proteolytic and/or amylolytic activity used in the context of the invention may therefore be of purely microbial origin or of purely animal origin, or alternatively represent a mixture of enzymes of animal and microbial origin.

Lipase-containing enzyme products of non-animal origin as well as preparations thereof, are enzyme mixtures comprising at least one lipase and optionally also at least one protease and/or amylase. These enzymes may be plant-derived or of fungal or bacterial origin. These lipases, proteases and/or amylases may, for example, be obtained by fermentation of optionally recombinant bacteria or fungi. The lipase-containing enzyme products may be composed of purely microbial derived enzyme preparations (i.e. enzymes obtained from fungi or bacteria) or enzyme preparations obtained from plants, but also of synthetic mixtures of enzyme preparations from plants, bacteria and/or fungi, optionally produced recombinantly in a microbial system. Furthermore, the recombinantly produced enzyme may be an enzyme variant or a mutated enzyme which is functionally equivalent or which has structural features similar to a naturally occurring enzyme.

By “recombinantly produced microbial enzyme”, in particular “recombinantly produced lipase, amylase or protease”, is meant an enzyme produced by recombinant DNA-technology, the enzyme being of microbial origin, i.e. obtained from fungi or bacteria. In the context of this invention suitable lipases include recombinantly produced microbial lipases that possess lipolytic activity, preferably at relatively low pH. In the context of this invention suitable proteases include recombinantly produced microbial proteases that possess proteolytic activity, preferably at relatively low pH. In the context of this invention suitable amylases include recombinantly produced microbial amylases that possess amylolytic activity, preferably at relatively low pH.

The recombinantly produced microbial enzyme, i.e. the lipase, amylase or protease, may be an enzyme variant or a mutated enzyme which is functionally equivalent or which has structural features similar to a naturally occurring enzyme.

Preferred recombinantly produced microbial lipases include lipases derived from fungi, e.g. from Humicola, Rhizomucor, Rhizopus, Geotrichum or Candida species, in particular Humicola lanuginosa (Thermomyces lanuginosa), Rhizomucor miehei, Rhizopus javanicus, Rhizopus arrhizus, Rhizopus oryzae, Rhizopus delamar, Candida cylindracea, Candida rugosa or Geotrichum candidum; or may be derived from bacteria, e.g. from Pseudomonas, Burkholderia or Bacillus species, in particular Burkholderia cepacia. Most preferred are lipases derived from a strain of Humicola lanuginosa (Thermomyces lanuginosa) or Rhizomucor miehei.

Lipases of microbial origin which can be used in the context of the present invention and their production by e.g. recombinant technology are described, for example, in U.S. Pat. No. 5,614,189 (=EP 600,868), U.S. Pat. No. 5,766,912 (=EP 238,023), U.S. Pat. No. 5,536,661 (=EP 305,216), U.S. Pat. No. 6,051,220 (=EP 828,509), U.S. Pat. No. 5,849,296 (=EP 550,450), US Patent Publication No. 2001/046493 (=EP 1,261368), U.S. Pat. No. 6,140,475 (=EP 973,878) and U.S. Pat. No. 5,489,530 (=EP 592,478), which publications are each hereby incorporated by reference.

Preferred recombinantly produced microbial amylases include amylases derived from fungi, e.g. from Aspergillus or Rhizopus species, in particular Aspergillus niger or Aspergillus oryzae; or may be derived from bacteria, e.g. from Bacillus species, in particular Bacillus subtilis. Amylases derived from a strain of Aspergillus oryzae are most preferred.

Amylases of microbial origin which can be used in the context of the present invention and their production by recombinant technology are described in e.g. U.S. Pat. No. 6,051,220 (=EP 828,509) which publication is hereby incorporated by reference.

Preferred recombinantly produced microbial proteases include proteases derived from fungi, e.g. from Aspergillus or Rhizopus species, in particular Aspergillus melleus, Aspergillus oryzae, Aspergillus niger, or Rhizopus oryzae; or may be derived from bacteria, e.g. from Bacillus species, in particular Bacillus subtilis. Most preferred are proteases derived from a strain of Aspergillus melleus.

Proteases of microbial origin which can be used in the context of the present invention are described in e.g. U.S. Pat. No. 6,767,729 (=EP 1,186,658), which is hereby incorporated by reference, and in Pariza M. W. & Johnson E. A., “Evaluating the safety of microbial enzyme preparations used in food processing: update for a new century.” Regul Toxicol Pharmacol. 2001 April; 33(2):173-86. (Review).

The recombinantly produced microbial enzyme, i.e. lipase, amylase or protease, preferably the recombinantly produced lipase, may be obtained by fermentation of a fungal cell, e.g. belonging to the genus Aspergillus, such as A. niger, A. oryzae, or A. nidulans; a yeast cell, e.g. belonging to a strain of Saccharomyces, such as S. cerevisiae, or a methylotrophic yeast from the genera Hansenula, such as H. polymorpha, or Phichia, such as P. pastoris; or a bacterial cell, e.g. belonging to a strain of Bacillus, such as B. subtilis, or B. lentus; the cell being transformed with the gene encoding the microbial lipase. Most preferred host organisms are members of Aspergillus oryzae.

An enzyme variant or mutated enzyme is obtainable by alteration of the DNA sequence of the parent gene or its derivatives. The enzyme variant or mutated enzyme may be expressed and produced when the DNA nucleotide sequence encoding the respective enzyme is inserted into a suitable vector in a suitable host organism. The host organism does not necessarily have to be identical to the organism from which the parent gene originated. The methods for introducing mutations into genes are well known in the art, see, for example, U.S. Pat. No. 5,658,871 (=EP 407, 225), the disclosure of which is incorporated by reference.

Preferred lipase variants or mutated lipases are obtainable from parent microbial lipases. In a preferred embodiment the parent lipase is derived from a fungus, e.g. a strain of Humicola or Rhizomucor, preferably a strain of Humicola lanuginosa or a strain of Rhizomucor miehei. In another preferred embodiment the parent lipase is derived from yeast, e.g. from a strain of Candida. In a further preferred embodiment the parent lipase is derived from a bacterium, e.g. from a strain of Pseudomonas. More preferred lipase variants or mutated lipases are lipase variants of parent lipases comprising a trypsin-like catalytic triad including an active serine residue located in a predominantly hydrophobic, elongated binding pocket of the lipase molecule, in which the electrostatic charge and/or hydrophobicity of a lipid contact zone comprising residues located in the vicinity of the lipase structure containing the active serine residue, which residues may participate in the interaction with the substrate at or during hydrolyzis, has been changed by deleting or substituting one or more negatively charged amino acid residues by neutral or positively charged amino acid residue(s), and/or by replacing one or more neutral amino acid residues with positively charged amino acid residue(s), and/or by deleting or substituting one or more hydrophobic amino acid residues by hydrophobic amino acid residue(s).

Pharmaceutically compatible auxiliaries, carriers and/or excipients useful in the context of the present invention are preferably selected from the group consisting of free polyethylene glycols having an average molecular weight of about 200 to about 6000; glycerol; lower alcohols, in particular straight-chain or branched C₁-C₄-alcohols such as 2-propanol; sugars, such as lactose, sucrose or dextrose; polysaccharides, such as maltodextrin or dextrates; starches; cellulosics, such as microcrystalline cellulose or microcrystalline cellulose/sodium carboxymethyl cellulose; inorganics, such as dicalcium phosphate, hydroxyapitite, tricalcium phosphate, talc, or titania; and polyols, such as mannitol, xylitol, sorbitol or cyclodextrin; and mixtures of the aforementioned substances.

The present invention includes pharmaceutical compositions for oral administration, which are self-emulsifiable on contact with a hydrophilic phase and a lipophilic phase, the compositions comprising:

-   -   (i) enzymes or enzyme mixtures with at least lipolytic activity,         and     -   (ii) a system comprising         -   at least one surfactant,         -   at least one co-surfactant, and         -   optionally a lipophilic phase.

Preferably the pharmaceutical composition according to the invention comprises enzymes or enzyme mixtures with at least lipolytic activity and a system comprising

-   -   at least one surfactant having an HLB value above 6 and below         18,     -   at least one co-surfactant having an HLB-value below 10, and     -   a lipidic (lipophilic) phase,     -   wherein the system comprising surfactant, co-surfactant and         lipophilic phase has an HLB value of about 4 to 16, and a         melting point of at least 20° C., preferably of at least 25° C.

The surfactant of the system is preferably selected from the group consisting of polyethylene glycol fatty acid esters; polyethylene glycol glycerol fatty acid esters; polyethylene glycol alkyl ethers, polyethylene glycol sterol ethers, polyethylene glycol sorbitan fatty acid esters, sugar esters, polyoxyethylene-polyoxypropylene block copolymers, ionic surfactants and mixtures thereof. Even more preferred, the surfactant is selected from the group consisting of polyethylene glycol (PEG) fatty acid mono- and/or di-esters with aliphatic C₆-C₂₂ carboxylic acids; polyethylene glycol (PEG) glycerol fatty acid esters with aliphatic C₆-C₂₂ carboxylic acids; polyethylene glycol (PEG) alkyl mono- and/or di-ethers with aliphatic C₁₂-C₁₈ alcohols, and mixtures thereof. In particular, the surfactant used is represented by a mixture of polyethylene glycol (PEG) mono- and di-esters with aliphatic C₆-C₂₂ carboxylic acids and/or polyethylene glycol (PEG) mono- and di-ethers with aliphatic C₁₂-C₁₈ alcohols, wherein the polyethylene glycol (PEG) comprises 6 to 60 ethylene oxide units per molecule (PEG-6 to PEG-60, also named as PEG 300 to PEG 3000). Preferably the surfactant is a mixture of polyethylene glycol mono- and di-esters with aliphatic C₆-C₂₂ carboxylic acids, wherein the polyethylene glycol comprises 6 to 40 ethylene oxide units per molecule.

The co-surfactant of the system is preferably selected from the group consisting of mono-acylglycerides, mono-ethers of glycerol, partial esters of propylenglycol, partial esters of polyglycerol, partial esters of ethyl diglycol and mixtures thereof. Even more preferred is a co-surfactant selected from the group consisting of mono-acylglycerides with aliphatic C₆-C₂₂ carboxylic acids, mono-ethers of glycerol ethers with aliphatic C₁₂-C₁₈ alcohols, partial esters of propylenglycol with aliphatic C₆-C₂₂ carboxylic acids, partial esters of polyglycerol with aliphatic C₆-C₂₂ carboxylic acids, and mixtures thereof. Particularly preferred co-surfactants are monoacylglycerides of aliphatic C₆-C₂₂ carboxylic acids and/or monoethers of glycerol with aliphatic C₁₂-C₂₂ alcohols, especially monoacylglycerides of aliphatic C₆-C₂₂ carboxylic acids.

The “lipophilic phase” is preferably represented by di- and/or triacylglycerides, especially preferably by di- and/or triacylglycerides with aliphatic C₆-C₂₂ carboxylic acids.

In one preferred embodiment, the system which is part of the pharmaceutical composition comprises

-   -   as surfactant a mixture of polyethylene glycol (PEG) mono- and         di-esters with aliphatic C₆-C₂₂ carboxylic acids and/or         polyethylene glycol (PEG) mono- and di-ethers with aliphatic         C₁₂-C₁₈ alcohols, in which the polyethylene glycol (PEG)         comprises 6 to 60 ethylene oxide units per molecule, preferably         a mixture of polyethylene glycol mono- and di-esters with         aliphatic C₆-C₂₂ carboxylic acids, in which the polyethylene         glycol comprises 6 to 40 ethylene oxide units per molecule;     -   as co-surfactant monoacylglycerides of aliphatic C₆-C₂₂         carboxylic acids and/or monoethers of glycerol with aliphatic         C₁₂-C₂₂ alcohols, preferably monoacylglycerides of aliphatic         C₆-C₂₂ carboxylic acids, and     -   as lipophilic phase di- and triacylglycerides of aliphatic         C₆-C₂₂ carboxylic acids.

In the pharmaceutical composition according to the invention the system preferably comprises:

-   -   2 to 90% by weight surfactants as defined above,     -   5 to 60% by weight co-surfactants as defined above, and     -   0 to 70% by weight of the lipophilic phase as defined above,     -   in which the components surfactant, co-surfactant and the         lipophilic phase together make up to 100% by weight of the         system, and in which the system consisting of surfactant,         co-surfactant and the lipophilic phase makes up 10% to 95% by         weight of the pharmaceutical composition.

Preferably, the system consisting of surfactant, co-surfactant and lipophilic phase makes up 10 to 70% by weight, preferably 20 to 50% by weight, more preferably 25 to 40% by weight, of the pharmaceutical composition.

In a further embodiment of the pharmaceutical composition according to the invention, the system comprises:

-   -   40 to 90% by weight, preferably 60 to 85% by weight,         surfactants,     -   5 to 40% by weight, preferably 15-30% by weight, co-surfactants,         and     -   0 to 40% by weight, preferably 15-30% by weight, of the         lipophilic phase,     -   and the total of co-surfactants and the lipophilic phase         together is at least 10% by weight, preferably between 15 and         40% by weight of the system.

In the context of the present invention, the pharmaceutical compositions may furthermore contain conventional pharmaceutically compatible auxiliaries, carriers and/or excipients as defined hereinafter.

In particular, the pharmaceutically compatible auxiliaries, carriers and/or excipients may be selected from the group consisting of free polyethylene glycols having an average molecular weight of about 200 to about 6000; glycerol; lower alcohols, in particular straight-chain or branched C₁-C₄-alcohols such as 2-propanol; sugars, such as lactose, sucrose or dextrose; cellulosics, such as microcrystalline cellulose or microcrystalline cellulose/sodium carboxymethyl cellulose; and mixtures of the aforementioned substances.

In a preferred embodiment, the proportion of the pharmaceutically compatible auxiliaries and/or excipients furthermore contained therein is at most 20% by weight of the pharmaceutical composition.

In a further preferred embodiment, the pharmaceutical composition according to the invention comprises a macrogolglyceride mixture representing the system consisting of surfactant, co-surfactant and lipophilic phase, in which the macrogolglycerides are a mixture of mono-, di- and tri-acylglycerides and polyethylene glycol (PEG) mono- and di-esters of aliphatic C₆-C₂₂ carboxylic acids, and optionally also small proportions of glycerol and free polyethylene glycol.

The polyethylene glycol (PEG) contained in the macrogolglyceride mixtures is preferably a PEG which has on average 6 to at most 40 ethylene oxide units per molecule or a molecular weight of between 200 and 2000.

One further aspect of the invention provides for the pharmaceutical composition to comprise a system consisting of surfactant, co-surfactant and lipophilic phase, the system having an HLB value of at least 10 and a melting point of at least 30° C. In a preferred embodiment, the system has an HLB value of 10 to 16, preferably of 12 to 15, and has a melting point of between 30 and 60° C., preferably between 40 and 50° C.

In particular, the system characterized by HLB value and melting point is a mixture of mono-, di- and triacylgylcerides and mono- and diesters of polyethylene glycol (PEG) with aliphatic carboxylic acids with 8 to 20 carbon atoms, in which the polyethylene glycol preferably contains about 6 to about 32 ethylene oxide units per molecule, and the system optionally contains free glycerin and/or free polyethylene glycol. The HLB value of such a system is preferably regulated by the chain length of the PEG. The melting point of such a system is regulated by the chain length of the fatty acids, the chain length of the PEG and the degree of saturation of the fatty-acid chains, and hence by the starting oil used for the preparation of the macrogolglyceride mixture.

The term “aliphatic C₈-C₁₈ carboxylic acids” designates mixtures in which caprylic acid (C8), capric acid (C10), lauric acid (C12), myristic acid (C14), palmitic acid (C16) and stearic acid (C18) are contained in a significant and variable proportion, if these acids are saturated, and the corresponding unsaturated C₈-C₁₈ carboxylic acids. The proportions of these fatty acids may vary depending on the starting oils.

Such a mixture of mono-, di- and triacylgylcerides and mono- and diesters of polyethylene glycol (PEG) with aliphatic carboxylic acids with 8 to 18 carbon atoms can, for example, be obtained by a reaction between a polyethylene glycol with a molecular weight of between 200 and 1500 and a starting oil, the starting oil consisting of a triglyceride mixture with fatty acids which are selected from the group consisting of caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid and linolenic acid, individually or as a mixture. Optionally, the product of such a reaction may also contain small proportions of glycerin and free polyethylene glycol.

Such a mixture is commercially available, for example, under the trade name Gelucire®. One advantageous embodiment of the invention provides that, of the products known under the trade name Gelucire®, in particular “Gelucire® 50/13” and/or “Gelucire® 44/14” represent suitable mixtures for use in the pharmaceutical preparations according to the invention.

Gelucire® 50/13 is a mixture in which mono-, di- and triacylglycerides and mono- and diesters of polyethylene glycol, with palmitic acid (C16) and stearic acid (C18) at 40% to 50% and 48% to 58%, respectively, making up the major proportion of bound fatty acids. The proportion of caprylic acid (C8) and capric acid (C10) is less than 3% in each case, and the proportion of lauric acid (C12) and myristic acid (C14) in each case is less than 5%.

A preferred embodiment of the present invention provides a pharmaceutical composition which comprises a system containing a mixture of mono-, di- and triacylglycerides and polyethylene glycol mono- and diesters of aliphatic C₈-C₁₈ carboxylic acids and optionally also small proportions of glycerin and free polyethylene glycol, the system having a melting point between 46° C. and 51° C. and an HLB value of around 13.

Gelucire® 44/14 is a mixture of mono-, di- and triacylgylcerides and mono- and diesters of polyethylene glycol, the respective proportions of palmitic acid (C16) being 4 to 25%, stearic acid (C18) 5 to 35%, caprylic acid (C8) less than 15%, capric acid (C10) less than 12%, lauric acid (C12) 30 to 50% and myristic acid (C14) 5 to 25%. Gelucire® 44/14 can, for example, be prepared by an alcoholysis/esterification reaction using palm kernel oil and polyethylene glycol 1500.

One preferred embodiment of the present invention provides a pharmaceutical composition which comprises a system containing a mixture of mono-, di- and triacylglycerides and polyethylene glycol mono- and diesters of aliphatic C₈-C₁₈ carboxylic acids and optionally also small proportions of glycerin and free polyethylene glycol, the system having a melting point between 42° C. and 48° C. and an HLB value of around 14.

In an alternative embodiment of the pharmaceutical composition of the invention, an ionic surfactant is used as surfactant. Preferably, the ionic surfactant is selected from the group consisting of lecithin, lysolecithin, phosphatidylcholine, phosphatidylethanola mine, phosphatidylglycerol, phosphatidylserine, lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylglycerol, lysophosphatidylinositol, lysophosphatidic acid, lysophosphatidylserine, and mixtures thereof. Lysophosphatidylcholine is especially preferred.

One particularly preferred pharmaceutical composition according to the invention comprises a system containing

-   -   as surfactant lysophosphatidylcholine,     -   as co-surfactant a mixture of mono-acylglycerides with aliphatic         saturated and/or unsaturated C₁₆-C₂₀ carboxylic acids,         preferably with oleic and/or linoleic acid, and     -   a lipophilic phase of di- and/or triacylglycerides with         aliphatic C₁₆-C₂₀ carboxylic acids, preferably with oleic and/or         linoleic acid.

As a commercially available mixture of mono-, di- and triacylglycerides with aliphatic saturated and/or unsaturated C₁₆-C₂₀ carboxylic acids Maisine® (Gattefosse) can be used.

Preferably, the pharmaceutical composition is one in which the system comprises 2 to 10%, preferably about 5%, by weight lysophosphatidylcholine, 28 to 51% by weight mono-acylglycerides mainly of oleic acid and linoleic acid, and 36 to 54% by weight di-acylglycerides and 4 to 20% by weight tri-acylglycerides mainly of oleic acid and linoleic acid, in which the system consisting of surfactant, co-surfactant and the lipophilic phase together makes up 10% to 30%, preferably about 20%, by weight of the pharmaceutical composition.

For the pharmaceutical preparations according to the invention, preferably solid orally administered dosage forms may be selected, for example powders, pellets, granules, tablets, or microspheres, which if desired may be filled into capsules or sachets or may be compressed to form tablets. Granules are preferably produced by melt granulation. Tablets are usually made from a powder or from melt granules. Pellets can be produced either by exploiting the thermoplastic properties of the auxiliaries in a heavy-duty mixer (melt pelletization) or by traditional methods e.g. extrusion (e.g. melt extrusion or wet extrusion) and spheronisation. If individual enzyme types are present and are obtained separately, such as a lipase, a protease or an amylase from microbial origin, these may either be mixed together or spatially separated from each other. If the individual enzymes are not spatially separated from each other, dry processing and/or storage is preferred.

The pharmaceutical compositions according to the invention, which are self-emulsifiable on contact with a hydrophilic phase and optionally a lipophilic phase, contain enzymes or enzyme mixtures with at least lipolytic activity as active substance. In a preferred variant of the present invention, the enzymes or enzyme mixtures may however, in addition to the lipolytic activity, also have proteolytic activity, i.e. contain at least one protease, and/or amylolytic activity, i.e. contain at least one amylase.

In one preferred variant of the present invention, the lipolytic activity of the enzymes or enzyme mixtures is provided by a microbial lipase.

In another embodiment, the pharmaceutical composition contains enzymes or enzyme mixtures which comprise pancreatin and/or are pancreatin-like, preferably pancreatin-containing mixtures of digestive enzymes. Preferably, the pancreatin and/or pancreatin-like mixtures of digestive enzymes make up 65-85%, in particular 75-80%, by weight, of the pharmaceutical composition.

Alternatively, the enzyme mixture used is a mixture of at least one microbial lipase and one or more microbial enzymes selected from the group consisting of proteases and amylases.

In one variant of the invention, the enzyme mixture used is purely of microbial origin. Examples of such physiologically acceptable bacterial and/or fungal enzymes have already been described in the prior art, together with procedures for obtaining these enzymes and for their use in the treatment of maldigestion. For example, such synthetic mixtures of lipase, protease and amylase, each of which are microbially obtained, and also pharmaceutical preparations containing these mixtures are described in US Patent Publication No. 2004/057944 (=WO 02/060474) and U.S. Pat. No. 6,051,220 (=EP 828,509).

Preferably, the pharmaceutical composition contains microbial enzymes making up 5-80%, in particular 20-60%, by weight of the pharmaceutical composition.

In the context of the invention, most preferred are those mixtures of digestive enzymes with lipolytic, proteolytic and amylolytic activity, the properties of which are close to those of pancreatin. Pancreatin-containing mixtures of digestive enzymes and also in particular pancreatin itself are therefore preferred in the context of the present invention as disclosed above. However it is possible, if desired, to add to the pancreatin or the pancreatin-containing mixtures of digestive enzymes one or more microbial enzymes, i.e. lipases, proteases and/or amylases obtained from microbial sources.

Suitable microbial enzymes for use as the sole enzyme mixture or as an addition to pancreatin or the pancreatin-containing mixtures of digestive enzymes include, in particular, bacterial or fungal enzymes, such as from the species Bacillus or Pseudomonas, or from fungal cultures, such as from the species Aspergillus, Humicola or Rhizomucor. Preferably, the microbial enzymes, in particular the microbial lipase, are recombinantly produced. In a further preferred variant of the present invention, the microbial lipase is a lipase variant or a mutated lipase.

The present invention furthermore relates to the use of a system comprising

-   -   at least one surfactant,     -   at least one co-surfactant, and     -   optionally a lipophilic phase         for stabilizing the lipolytic activity in the acidic pH range         and/or for improving the lipolytic activity of solid         pharmaceutical preparations containing enzymes or enzyme         mixtures with at least lipolytic activity, preferably pancreatin         or pancreatin-like mixtures of digestive enzymes.

The possible further configurations of the system to be used, consisting of surfactant, co-surfactant and lipophilic phase, correspond to the embodiments described above for the self-emulsifiable pharmaceutical preparation according to the invention, which comprises such a system.

The invention also relates to a process for the preparation of solid pharmaceutical preparations containing enzymes or enzyme mixtures with at least lipolytic and optionally also proteolytic and/or amylolytic activity, preferably pancreatin and/or pancreatin-like mixtures of digestive enzymes. According to the invention, the enzymes or enzyme mixtures are converted into a suitable medicament form together with a system comprising

-   -   a surfactant selected from the group consisting of polyethylene         glycol fatty acid esters, polyethylene glycol glycerol fatty         acid esters, polyethylene glycol alkyl ethers, polyethylene         glycol sterol ethers, polyethylene glycol sorbitan fatty acid         esters, sugar esters, polyoxyethylene-polyoxypropylene block         copolymers, ionic surfactants, and mixtures thereof;     -   a co-surfactant selected from the group consisting of         mono-acylglycerides, mono-ethers of glycerol, partial esters of         propylenglycol, partial esters of polyglycerol, partial esters         of ethyl diglycol, and mixtures thereof, and     -   a lipophilic phase, which is represented by di- and/or         triacylglycerides,         and also optionally conventional, pharmaceutically compatible         auxiliaries, carriers and/or excipients.

The further possible configurations of the system consisting of surfactant, co-surfactant and lipophilic phase used in the preparation process correspond to the embodiments described above for the self-emulsifiable pharmaceutical preparation according to the invention, which comprises such a system.

The following examples are intended to illustrate the invention in further detail without limiting its scope:

EXAMPLE 1

Preparation of pancreatin-containing compositions according to the invention and comparison of the lipolytic activity of a conventional pancreatin formulation and a pancreatin formulation according to the invention comprising a system consisting of a surfactant, co-surfactant and lipophilic phase

a) Conventional Preparation (Pellets) not According to the Invention

The conventional formulation was prepared according to the process disclosed in U.S. Pat. No. 5,378,462 (=EP 583,726). 120 g pancreatin and 30 g PEG 4000 were initially dry-mixed and then moistened with 20 g isopropanol. The moist mixture was extruded and then rounded in a suitable rounder with the aid of paraffin oil. The resulting pellets were then dried.

b) Preparation According to the Invention (Pellets) Example 1A

350 g Gelucire® 50/13 was melted in a beaker in a water bath at a temperature of 52° C. The molten mass was mixed with 650 g pancreatin in a dual-jacket mixer for 10 min. The homogenous mixture was placed in a melt extruder for extrusion. Then the extrudate was rounded in a suitable rounder or spheroniser. The resulting pellets had a diameter of 1.0-1.6 mm.

c) Preparation According to the Invention (Granules) Example 1B

300 g Gelucire® 44/14 was melted in a beaker in a water bath at a temperature of 48° C. The molten mass was mixed with 700 g pancreatin in a dual-jacket mixer for approximately 15 minutes and then cooled (melt granulation).

The activity of the lipase as a function of the pH value and the time-dependent change in lipase activity were determined in accordance with the method of the “Fédération Internationale Pharmaceutique/European Pharmacopeia” (abbreviated hereinafter as FIP/Ph.Eur.). In this standard analysis method, the hydrolytic activity of the lipase in the sample to be investigated is determined with the substrate olive oil. The free fatty acids cleaved off from the triglycerides of the olive oil are titrated with sodium hydroxide solution at a constant pH of 9.0. The lipase activity of the sample is determined by comparing the rate at which the sample hydrolyzes an olive oil emulsion with the rate at which a suspension of a standard pancreas reference powder hydrolyzes the same substrate under the same conditions.

The absolute and relative lipolytic activity of the conventional preparation and the preparation 1A according to the invention (pellets) determined in each case in accordance with FIP/Ph.Eur. are summarized in the following Table 1. The absolute and relative lipolytic activity of the conventional preparation and the preparation 1B according to the invention (granules) determined in each case in accordance with FIP/Ph.Eur. are summarized in the following Table 2:

TABLE 1 Absolute and relative lipolytic activity of the standard preparation and the preparation according to the invention (pellets with Gelucire ® 50/13) Lipase activity Theoretically present Measured Relative starting lipase activity in the absolute lipase lipase pancreatin formulation activity activity Sample [U/g] [U/g] [U/g] [%] Example 1A: 92620 60203 63173 104 Pellets Conventional 92620 74096 69650 94 formulation

TABLE 2 Absolute and relative lipolytic activity of the standard preparation and the preparation according to the invention (granules with Gelucire ® 44/14) Lipase activity Theoretically present Determined Relative starting lipase activity in the absolute lipase lipase pancreatin formulation activity activity Sample [U/g] [U/g] [U/g] [%] Example 1B: 84787 59351 67653 114 Granules Conventional 84132 67306 64950 97 formulation

It is apparent from the data that the addition of systems comprising at least one surfactant, at least one co-surfactant and a lipophilic phase to pharmaceutical preparations of enzymes and enzyme mixtures with at least lipolytic activity, preferably pancreatin and/or pancreatin-like mixtures of digestive enzymes, contributes to improved lipolytic activity compared with conventional formulations of pancreatin known in the prior art.

The absolute lipolytic activity of the respective pharmaceutical preparation determined in accordance with FIP/Ph.Eur. is expressed with reference to the total lipolytic activity theoretically present in the sample in the form of a relative activity, in order to take account of the different concentrations of pancreatin in the formulations. Comparison of the relative lipase activities determined shows that the relative lipase activity of the preparations according to the invention is approximately 10% higher than those of the conventional formulations. Accordingly, the pharmaceutical preparations according to the invention have increased lipolytic activity compared with conventional pancreatin formulations.

Furthermore, with reference to the value of the relative lipase activity of the preparation according to the invention of more than 100%, it is apparent that the system consisting of surfactant, co-surfactant and optionally lipophilic phase added to the preparations according to the invention exerts an activating effect on the lipase.

EXAMPLE 2

Comparison of the stability of lipolytic activity of a conventional pancreatin formulation and a pancreatin formulation according to the invention comprising a system consisting of a surfactant, co-surfactant and lipophilic phase at different pH values

In order to compare the stability of lipolytic activity of a conventional pancreatin formulation and a pharmaceutical formulation according to the invention comprising an enzyme mixture with at least lipolytic activity and a system consisting of at least one surfactant, at least one co-surfactant, and a lipophilic phase, the activity of such a conventional pancreatin formulation was compared with the activity of a mixture of Gelucire® and pancreatin incubated for up to 2 hours at different pH values (pH 6, pH 5 and pH 4).

a) Standard Preparation (Pellets)

The conventional formulation was prepared according to the process disclosed in U.S. Pat. No. 5,378,462. 120 g pancreatin and 30 g PEG 4000 were initially dry-mixed and then moistened with 20 g isopropanol. The moist mixture was extruded and then rounded in a suitable rounder with the aid of paraffin oil. The resulting pellets were then dried.

b) Preparation According to the Invention (Pellets) EXAMPLE 2

300 g Gelucire® 44/14 was melted in a beaker in a water bath at a temperature of 48° C. The molten mass was mixed with 700 g pancreatin in a dual-jacket high-speed mixer (melt pelletization).

The activity of the lipase as a function of the pH value and also the time-dependent change in lipase activity were determined in accordance with the method of the FIP/Ph.Eur. as described above.

To determine the release behavior of the lipase in the conventional preparation and the preparation according to the invention at different pH values, the samples were incubated in a decomposition apparatus for 2 hours at 37° C. in phosphate buffer solution (pH 6, pH 5, pH 4). Samples were taken at intervals of 15 minutes, and the lipolytic activity in the samples was determined in accordance with the FIP/Ph.Eur. method described above.

600 ml buffer (67 mM phosphate, 34 mM NaCl, pH 6.0, pH 5.0, pH 4.0) was heated to a constant temperature of 37° C. in a 1 liter beaker in the decomposition tester. Once the constant temperature had been reached, 2 g of sample was added to the beaker and the decomposition tester was set in motion. The pH value of the phosphate buffer was kept constant during the testing time. Samples were taken at intervals of 15 minutes in each case, and the lipolytic activity in the samples was determined in accordance with FIP/Ph.Eur.

The relative lipolytic activities of the conventional preparation and the preparation according to the invention determined after 15, 30, 45, 60, 75, 90, 105 and 120 minutes in accordance with FIP/Ph.Eur. are summarised in the following Table 3. Details are given in % of the activity of the respective sample compared with a standard pancreas reference powder in accordance with FIP/Ph.Eur.

TABLE 3 pH-dependency of the relative lipolytic activity of a conventional pancreatin formulation and a pancreatin preparation according to the invention PH 6 5 4 Time Conventional Conventional Conventional [min] formulation Example 2 formulation Example 2 formulation Example 2 15 93 98 89 100 30 55 30 90 101 82 99 19 39 45 84 97 77 95 13 31 60 81 89 72 95 11 27 75 79 82 71 94 8 23 90 76 76 68 92 7 19 105 72 71 65 89 6 18 120 69 66 61 86 5 17

It can be seen from this data that the addition of systems consisting of at least one surfactant, at least one co-surfactant, and a lipophilic phase to pharmaceutical preparations of enzymes and enzyme mixtures having at least lipolytic activity, preferably pancreatin and/or pancreatin-like mixtures of digestive enzymes, contributes to stabilizing the lipolytic activity in the acidic pH range. At a pH value of 6, comparison of the lipolytic activity of a conventional pancreatin preparation and a pancreatin preparation according to the invention over a time of 120 minutes shows that the lipolytic activity in both preparations over time decreases only relatively slightly, with the lipolytic activity of the preparation according to the invention increased by approximately 10% compared with the conventional formulation again being observed within the first hour. However, a pH value of 6 is known not to have any great influence on the lipolytic activity. On the other hand, at a pH value of 5 the lipolytic activity of the conventional preparation decreases much more quickly compared with the preparation according to the invention. Whereas the preparation according to the invention has lost less than 10% of the lipolytic activity after 90 minutes, the conventional preparation has only a lipolytic activity of less than 70% remaining compared with a pancreas reference powder in accordance with FIP/Ph.Eur. In particular at a pH value of 4, the preparation according to the invention has a markedly greater lipolytic (residual) activity than the conventional preparation. Accordingly, it can be seen that the pharmaceutical preparations according to the invention have a substantially increased lipolytic activity in an acidic pH medium.

EXAMPLE 3

Dosage dependence of a pancreatin formulation according to the invention comprising a system consisting of a surfactant, co-surfactant and lipophilic phase on digestibility of a high fat diet in the pancreatic exocrine deficient minipig

The efficacy of a pelleted pharmaceutical formulation according to the invention comprising an enzyme mixture with at least lipolytic activity and a system consisting of at least one surfactant, at least one co-surfactant, and a lipophilic phase to improve digestion and absorption of fat in minipigs, in which the pancreatic duct has been ligated to induce a complete pancreatic exocrine insufficiency, was analyzed in pigs fed a high (32%) fat diet.

a) Preparation According to the Invention (Pellets)

250 g Gelucire® 44/14 (Gattefosse) was melted in a beaker in a water bath at a temperature of 48° C. The molten mass was mixed with 750 g pancreatin in a dual-jacket high-speed mixer (melt pelletization). The pellet size of this formulation was similar to that of the commercially available pancreatin product.

Determination of the Activity of Lipase

Studies were performed in 6 minipigs (Ellegaard, female Göttingen minipigs) with induced pancreatic exocrine insufficiency, weighing 20-30 kg at surgery. The pigs were prepared as previously described by Tabeling R., Gregory P., Kamphues J., 1999: Studies on nutrient digestibilities (pre-caecal and total) in pancreatic duct-ligated pigs and the effects of enzyme substitution. J. Anim. Physiol. a. Anim. Nutr. 82, 251-263. The pancreatic duct was ligated under halothane anaesthesia following a mid-line laparotomy; after which the pigs were chronically fitted with an ileo-caecal re-entrant fistula which was exteriorized on the right flank.

The success of the pancreatic duct ligation was confirmed by a faecal chymotrypsin test before starting the digestibility studies, which began at least 4 weeks after the pigs had recovered from the surgery.

The pigs were fed two 250 g meals/day (08.00 and 20.00 h) of a high fat diet (containing: 180g double-milled Altromin 9021 [modified], 70 g soya oil [Roth]; overall contents are 99% dry matter, 4% crude ash, 32% crude fat, 16% crude protein, 28% starch, 3% crude fiber) plus 0.625 g Cr₂O₃ per meal, mixed with 1 liter water. The meals plus enzymes were carefully mixed together immediately before offering to the pigs. The meals were generally consumed within 5 minutes.

During the study the pigs received zero, 28,000 or 336,000 FIP lipase units per meal as a formulation according to the invention for 14 days, with a complete collection of faeces for the last 5 days. The faeces (and the feed) were frozen at −20° C., freeze dried, and a Weender analysis was performed [Naumann C, Bassler R. 1993: Die chemische Untersuchung von Futtermitteln. 3. Aufl. VDLUFA-Verlag, Darmstadt] to determine content of dry matter (drying at 103° C. for 8 hours), and crude fat (determined gravimetrically after boiling for 30 minutes with conc. HCl, followed by a 6 hours extraction with petroleum ether). Cr₂O₃ was oxidized to chromate, and chromium content was calculated via extinction at 365 nm [Petry H, Rapp W. 1970: Zur Problematik der Chromoxidbestimmung in Verdauungsversuchen. Z. Tierphysiol. Tierernährung and Futtermitellkunde 27, 181-189].

Based on the content of fat and chromium determined per 100 g dry matter feed and faeces (see above), the digestibility of fat (CFA) was calculated according to the formula:

${\% \mspace{14mu} {fat}\mspace{14mu} {digestibility}} = {100 - \left( {\frac{\left\lbrack {\% \mspace{14mu} {Cr}_{2}O_{3}\mspace{11mu} {in}\mspace{14mu} {feed}} \right\rbrack}{\left\lbrack {\% \mspace{14mu} {Cr}_{2}O_{3}\mspace{14mu} {in}\mspace{14mu} {faeces}} \right\rbrack} \times \frac{\left\lbrack {\% \mspace{14mu} {fat}\mspace{14mu} {in}\mspace{14mu} {faeces}} \right\rbrack}{\left\lbrack {\% \mspace{14mu} {fat}\mspace{14mu} {in}\mspace{14mu} {feed}} \right\rbrack} \times 100} \right)}$

The efficacy to improve digestion and absorption of fat in minipigs, in which the pancreatic duct has been ligated to induce a complete pancreatic exocrine insufficiency, measured in the % fat digestibility is given for the preparation according to the invention for different amounts of lipase activity added (given in FIP/Ph.Eur. units).

TABLE 4 % fat digestibility in minipigs receiving a pancreatin preparation according to the invention 0 Lipase 28,000 FIP lipase 336,000 FIP lipase Substitution Units U/meal U/meal No enzymes added 31.66 ± 13.78 Formulation 61.98 ± 11.60 * 79.25 ± 7.00 ** according to the invention *; ** Results are mean ± S.D.

It can be seen that the formulation according to the invention caused a very strong and dose-dependent improvement in fat digestibility, already showing a highly efficient improvement at the lower dose tested.

EXAMPLE 4

Comparison of the stability of lipolytic activity of a conventional pancreatin powder and a pancreatin formulation according to the invention comprising a system consisting of a surfactant, co-surfactant and lipophilic phase at different pH values

Further preparations according to the invention were prepared and analyzed with regard to their lipolytic activity in comparison to pancreatin powder at different acidic pH values (pH 6, pH 5 and pH 4).

a) Preparation for Comparison not According to the Invention:

-   Pancreatin powder

b) Preparation According to the Invention EXAMPLE 4A

-   700 g Pancreatin powder -   200 g Gelucire™ 44/14 (Gattefosse) -   100 g Labrasol™ (Gattefosse)

The Gelucire® 44/14 and the Labrasol® were mixed and melted in a beaker in a water bath at a temperature of 48° C. The molten mass was mixed with 700 g pancreatin in a dual-jacket high-speed mixer (melt granulation).

c) Preparation According to the Invention EXAMPLE 4B

-   800 g Pancreatin powder -   190 g Maisine (Gattefosse) -   10 g LPC (Lysophosphatidylcholine)

The Maisine® and the Lysophosphatidylcholine were mixed and melted in a beaker in a water bath at a temperature of 48° C. The molten mass was mixed with 800 g pancreatin in a dual-jacket high-speed mixer (melt granulation).

The activity of the lipase as a function of the pH value and also the time-dependent change in lipase activity were determined as described in Example 2.

The release behavior of the lipase at different pH values in the pancreatin powder and the preparation according to the invention was measured as described above for Example 2.

The relative lipolytic activity determined after 15, 30, 45, 60, 75, 90, 105 and 120 minutes of the pancreatin powder and the preparations “Example 4A” and “Example 4B” according to the invention in accordance with FIP/Ph.Eur. are summarized in the following Tables 5A and 5B. Details are given in % of the activity of the respective sample compared with a standard pancreas reference powder in accordance with FIP/Ph. Eur.

TABLE 5A pH-dependency of the relative lipolytic activity of a standard pancreatin powder and the pancreatin preparation “4A” according to the invention pH 6 5 4 Time Pancreatin Exam- Pancreatin Exam- Pancreatin Example [min] Powder ple 4A Powder ple 4A Powder 4A 15 55.7 90.4 61.5 93.8 19.3 49.0 30 54.9 105.1 53.3 99.0 12.5 32.4 45 48.3 102.9 51.8 95.8 8.4 25.5 60 43.1 97.6 48.1 92.7 6.5 23.1 75 39.0 91.7 41.4 93.2 5.6 19.9 90 35.4 87.2 39.9 91.2 4.3 18.8 105 33.0 82.3 44.8 88.1 3.9 17.8 120 30.4 79.2 39.1 85.6 3.6 16.5

TABLE 5B pH-dependency of the relative lipolytic activity of a standard pancreatin powder and the pancreatin preparation “4B” according to the invention pH 6 5 4 Time Pancreatin Exam- Pancreatin Exam- Pancreatin Example [min] Powder ple 4B Powder ple 4B Powder 4B 15 55.7 91.9 61.5 83.2 19.3 27.1 30 54.9 87.4 53.3 88.0 12.5 16.4 45 48.3 81.2 51.8 86.3 8.4 13.0 60 43.1 73.7 48.1 83.5 6.5 9.9 75 39.0 69.8 41.4 83.8 5.6 8.9 90 35.4 63.8 39.9 80.0 4.3 7.8 105 33 57.1 44.8 78.4 3.9 6.5 120 30.4 53.0 39.1 74.0 3.6 4.9

From these data it can be concluded that the addition of systems consisting of at least one surfactant, at least one co-surfactant, and a lipophilic phase to pharmaceutical preparations of enzymes and enzyme mixtures with at least lipolytic activity, preferably pancreatin and/or pancreatin-like mixtures of digestive enzymes, contributes to stabilizing the lipolytic activity in the acidic pH range.

EXAMPLE 5

Determination of the lipolytic activity of a formulation according to the invention comprising a lipase of microbial origin and a system consisting of a surfactant, co-surfactant and lipophilic phase and determination of stability at different pH values

In order to determine the lipolytic activity and to show the improved stability at acidic pH of a pharmaceutical formulation according to the invention comprising an enzyme mixture with at least lipolytic activity, in which the lipolytic activity is provided by a microbial, optionally recombinantly produced lipase, and a system consisting of at least one surfactant, at least one co-surfactant, and a lipophilic phase, the activity of a pharmaceutical formulation consisting of a mixture of Gelucire™ and a microbial lipase is determined at different pH values (pH 6, pH 5, pH 4 and 3) and compared to a lipase preparation which has not been stabilized.

a) Preparation According to the Invention (Granulate)

562.5 g Gelucire® 44/14 was melted in a beaker in a water bath at a temperature of 48° C. 937.5 g of a microbial lipase preparation (the active lipase protein representing about 50 to 60% (w/w) of the dry matter of the preparation) were provided in a dual-jacket mixer at 46° C., then the molten Gelucire was added and the compounds were mixed, first at low speed for 3 min, then for approx. 15 min. at high speed, and finally cooled (melt granulation).

b) Comparison Preparation (not According to the Invention)

A microbial lipase preparation was prepared by using common spray dry technique.

The activity of the lipase was determined in accordance with the method of the “Federation Internationale Pharmaceutique” (abbreviated hereafter to FIP) for microbial lipases, except that the concentration of bile salts is 10 mM.

Using this standard analysis method, the hydrolytic activity of the lipase in the sample to be investigated is determined using olive oil as a substrate. Released free fatty acids are titrated with sodium hydroxide solution at a constant pH of 7.0. The lipase activity of the sample is determined by comparison of the rate at which the sample hydrolyzes an olive oil emulsion with the rate at which a suspension of a microbial lipase reference powder hydrolyzes the same substrate under the same conditions.

To determine the pH-stability of the lipase at different pH values in an unstabilized preparation and in the preparation according to the invention, the samples were incubated in a decomposition apparatus for 2 hours at 37° C. in buffer solution (pH 5, pH 4 and pH 3). Samples were taken at intervals of 15 minutes, and the lipolytic activity in the samples was determined in accordance with the FIP method.

100 mg of lipase were incubated in 100 ml buffer (0.1 M malonic acid buffer, 1 mM calcium chloride pH 3, 4 and 5) at 37° C. Samples were drawn every 15 mM for a total duration of 2 hours and the lipolytic activity of the samples was determined as follows: An olive oil suspension was prepared by mixing 175 g olive oil with 630 ml of a solution of 700 g of gum arabic and 94.4 g calcium chloride di-hydrate in 5,900 ml water for 15 minutes in a food mixer at maximal speed. The emulsion was cooled to 37° C., and the pH was adjusted to pH 6.8 with sodium hydroxide solution. Three reference solutions were prepared by extracting an appropriate amount of FIP microbial lipase standard with an ice-cold 1% (m/v) solution of sodium chloride such that reference solutions with 50 FIP-U/ml, 65 FIP-U/ml and 80 FIP-U/ml were obtained. Sample solutions were prepared by extracting an amount of sample corresponding to app. 6,500 units activity for 15 minutes with a total of 100 ml ice-cold 1% (m/v) solution of sodium chloride. The samples were further diluted in ice-cold 1% (m/v) solution of sodium chloride such that the titration rate was within the range of the titration rates obtained with the reference solutions.

The titration rates of the reference and sample solutions were determined by combining in a thermostated vessel 19 ml of olive oil suspension with 10 ml of a solution of 492 mg lipase activating mixture (FIP) in 500 ml of water. The combined solutions were thermostated to 37° C., and the pH was adjusted to pH 7.0. One ml of reference solution or sample solution were added, and the released fatty acids titrated under pH stable conditions with 0.1 M sodium hydroxide solution for a duration of 5 minutes. The titration rate was calculated by linear regression from at least 9 measurement points between the 60th and the 300th second of titration.

From the titration rates of the reference solutions a calibration function was calculated by linear regression. The calibration function takes the form y=mx+b where y: titration rate; m: slope; x: FIP-units of the reference solution; and b: axis intercept. Using the values thus determined for m and b, the lipolytic activity x was calculated for each sample solution using the formula x=(y−b)/m.

The relative lipolytic activities determined after 0, 15, 30, 45, 60, 75, 90, 105 and 120 minutes of an un-stabilized microbial lipase preparation and the preparation according to the invention in accordance with FIP are determined. A comparison of the results obtained can show the improved lipolytic activity and the increased stability within the acidic pH range of the formulation according to the invention comprising a microbial lipase preparation over the un-stabilized lipase preparation.

The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations within the scope of the appended claims and equivalents thereof. 

What is claimed is:
 1. A pharmaceutical composition for oral administration, which is self-emulsifiable on contact with a hydrophilic phase and a lipophilic phase, said composition comprising: an enzyme or enzyme mixture having at least lipolytic activity, and (ii) a system comprising at least one surfactant, and at least one co-surfactant.
 2. A pharmaceutical composition according to claim 1, wherein the hydrophilic phase used to form the final emulsion after ingestion is supplied by the physiological fluid of the digestive milieu.
 3. A pharmaceutical composition according to claim 1, wherein the lipophilic phase used to form the final emulsion in the digestive tract after ingestion is at least partially supplied by the lipids present in ingested food.
 4. A pharmaceutical composition according to claim 1, wherein the system furthermore comprises a lipophilic phase.
 5. A pharmaceutical composition according to claim 4, wherein the system comprises as surfactant at least one agent having a hydrophilic-lipophilic balance value above 6 and below 18, as co-surfactant at least one agent having a hydrophilic-lipophilic balance value below 10, and as lipophilic phase a lipidic phase, said system comprising surfactant, co-surfactant and lipophilic phase having a hydrophilic-lipophilic balance value of about 4 to 16, and a melting point of at least 20° C.
 6. A pharmaceutical composition according to claim 5, wherein said system has a melting point of at least 25° C.
 7. A pharmaceutical composition according to claim 4, wherein the system comprises a surfactant selected from the group consisting of polyethylene glycol fatty acid esters; polyethylene glycol glycerol fatty acid esters; polyethylene glycol alkyl ethers, polyethylene glycol sterol ethers, polyethylene glycol sorbitan fatty acid esters, sugar esters, polyoxyethylene-polyoxypropylene block copolymers, ionic surfactants and mixtures thereof; a co-surfactant selected from the group consisting of mono-acylglycerides, mono-ethers of glycerol, partial esters of propylenglycol, partial esters of polyglycerol, partial esters of ethyl diglycol and mixtures thereof, and a lipophilic phase represented by di- and/or triacylglycerides.
 8. A pharmaceutical composition according to claim 7, wherein the system comprises a surfactant selected from the group consisting of polyethylene glycol fatty acid mono- and/or di-esters with aliphatic C₆-C₂₂ carboxylic acids; polyethylene glycol glycerol fatty acid esters with aliphatic C₆-C₂₂ carboxylic acids; polyethylene glycol alkyl mono- and/or di-ethers with aliphatic C₁₂-C₁₈ alcohols, and mixtures thereof; a co-surfactant selected from the group consisting of mono-acylglycerides with aliphatic C₆-C₂₂ carboxylic acids, mono-ethers of glycerol ethers with aliphatic C₁₂-C₁₈ alcohols, partial esters of propylenglycol with aliphatic C₆-C₂₂ carboxylic acids, partial esters of polyglycerol with aliphatic C₆-C₂₂ carboxylic acids, and mixtures thereof, and a lipophilic phase represented by di- and/or triacylglycerides with aliphatic C₆-C₂₂ carboxylic acids.
 9. A pharmaceutical composition according to claim 8, wherein the system comprises as surfactant a mixture of polyethylene glycol mono- and di-esters with aliphatic C₆-C₂₂ carboxylic acids and/or polyethylene glycol mono- and di-ethers with aliphatic C₁₂-C₁₈ alcohols, whereby the polyethylene glycol comprises 6 to 60 ethylene oxide units per molecule, as co-surfactant monoacylglycerides of aliphatic C₆-C₂₂ carboxylic acids and/or monoethers of glycerol with aliphatic C₁₂-C₂₂ alcohols, and as lipophilic phase di- and triacylglycerides of aliphatic C₆-C₂₂ carboxylic acids.
 10. A pharmaceutical composition according to claim 9, wherein a mixture of polyethylene glycol mono- and di-esters with aliphatic C₆-C₂₂ carboxylic acids, whereby the polyethylene glycol comprises 6 to 40 ethylene oxide units per molecule, are used as surfactant, and monoacylglycerides of aliphatic C₆-C₂₂ carboxylic acids are used as co-surfactant.
 11. A pharmaceutical composition according to claim 4, wherein the system comprises 2 to 90% by weight surfactants, 5 to 60% by weight co-surfactants, and 0 to 70% by weight of the lipophilic phase, whereby the components surfactant, co-surfactant and the lipophilic phase together make up to 100% by weight of the system, and the system makes up 10% to 95% by weight of the pharmaceutical composition.
 12. A pharmaceutical composition according to claim 11, wherein the system consisting of surfactant, co-surfactant and lipophilic phase makes up 10 to 70% by weight of the pharmaceutical composition.
 13. A pharmaceutical composition according to claim 12, wherein the system consisting of surfactant, co-surfactant and lipophilic phase makes up 20 to 50% by weight of the pharmaceutical composition.
 14. A pharmaceutical composition according to claim 13, wherein the system consisting of surfactant, co-surfactant and lipophilic phase makes up 25 to 40% by weight of the pharmaceutical composition.
 15. A pharmaceutical composition according to claim 11, wherein the system comprises 40 to 90% by weight surfactants, 5 to 40% by weight co-surfactants, and 0 to 40% by weight of the lipophilic phase, the total of co-surfactants and the lipophilic phase together being at least 10% by weight of the system.
 16. A pharmaceutical composition according to claim 15, wherein the system comprises 60 to 85% by weight surfactants, 15-30% by weight co-surfactants, and 15-30% by weight of the lipophilic phase, the total of co-surfactants and the lipophilic phase together being between 15 and 40% by weight of the system.
 17. A pharmaceutical composition according to claim 4, wherein the composition contains at least one further pharmaceutically compatible auxiliary, carrier or excipient selected from the group consisting of polyethylene glycol, glycerol, C₁-C₄-alcohols, sugars, cellulosics and mixtures thereof.
 18. A pharmaceutical composition according to claim 17, wherein said at least one further pharmaceutically compatible auxiliary, carrier, or excipient makes up a maximum of 20% by weight of the composition.
 19. A pharmaceutical composition according to claim 4, wherein macrogolglycerides represent the system comprising surfactant, co-surfactant and lipophilic phase and optionally also small proportions of glycerin and free polyethylene glycol, wherein the macrogolglycerides are a mixture of mono-, di- and triacylglycerides and polyethylene glycol mono- and diesters of aliphatic C₆-C₂₂ carboxylic acids, with the polyethylene glycol comprising about 6 to about 32 ethylene oxide units per molecule.
 20. A pharmaceutical composition according to claim 19, wherein the system comprising surfactant, co-surfactant and lipophilic phase has a hydrophilic-lipophilic balance value of at least 10, and a melting point of at least 30° C.
 21. A pharmaceutical composition according to claim 20, wherein the system has a hydrophilic-lipophilic ratio of 10 to 16, and a melting point of between 30 and 60° C.
 22. A pharmaceutical composition according to claim 21, wherein the system has a hydrophilic-lipophilic ratio of 12 to 15, and a melting point of between 40 and 50° C.
 23. A pharmaceutical composition according to claim 21, wherein the system contains a mixture of mono-, di- and triacylglycerides and polyethylene glycol mono- and diesters of aliphatic C₈-C₁₈ carboxylic acids, and optionally small proportions of glycerol and/or free polyethylene glycol, and has a melting point between 42° C. and 48° C. and an HLB value of around
 14. 24. A pharmaceutical composition according to claim 21, wherein the system contains a mixture of mono-, di- and triacylglycerides and polyethylene glycol mono- and diesters of aliphatic C₈-C₁₈ carboxylic acids and optionally small proportions of glycerol and free polyethylene glycol, the system having a melting point between 46° C. and 51° C. and an HLB value of around
 13. 25. A pharmaceutical composition according to claim 19, wherein the system contains a mixture of mono-, di- and triacylglycerides and polyethylene glycol PEG-32 mono- and diesters mainly of aliphatic C₈-C₁₆ carboxylic acids, a mixture of mono-, di- and triacylglycerides and polyethylene glycol PEG-8 mono- and diesters mainly of aliphatic C₆-C₁₀ carboxylic acids and optionally small proportions of glycerol and free polyethylene glycol.
 26. A pharmaceutical composition according to claim 7, wherein the surfactant is an ionic surfactant.
 27. A pharmaceutical composition according to claim 26, wherein the ionic surfactant is selected from the group consisting of lecithin, lysolecithin, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine, lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylglycerol, lysophosphatidylinositol, lysophosphatidic acid, lysophosphatidylserine, and mixtures thereof.
 28. A pharmaceutical composition according to claim 27, wherein the ionic surfactant is lysophosphatidylcholine.
 29. A pharmaceutical composition according to claim 27, wherein the system comprises as surfactant lysophosphatidylcholine, as co-surfactant a mixture of mono-acylglycerides with aliphatic saturated and/or unsaturated C₁₆-C₂₀ carboxylic acids, and a lipophilic phase represented by di- and/or triacylglycerides with aliphatic C₁₆-C₂₀ carboxylic acids.
 30. A pharmaceutical composition according to claim 29, wherein the co-surfactant is a mixture of mono-acylglycerides with oleic and/or linoleic acid, and the lipophilic phase is represented by di- and/or triacylglycerides with oleic and/or linoleic acid.
 31. A pharmaceutical composition according to claim 29, wherein the system comprises 2 to 10% by weight lysophosphatidylcholine, 28 to 51% by weight mono-acylglycerides mainly of oleic acid and linoleic acid, and 36 to 54% by weight di-acylglycerides and 4 to 20% by weight tri-acylglycerides mainly of oleic acid and linoleic acid, whereby the system consisting of surfactant, co-surfactant and the lipophilic phase together makes up 10% to 30% by weight of the pharmaceutical composition.
 32. A pharmaceutical composition according to claim 31, wherein the system comprises 5%, by weight lysophosphatidylcholine, 28 to 51% by weight mono-acylglycerides mainly of oleic acid and linoleic acid, and 36 to 54% by weight di-acylglycerides and 4 to 20% by weight tri-acylglycerides mainly of oleic acid and linoleic acid, whereby the system consisting of surfactant, co-surfactant and the lipophilic phase together makes up 20% by weight of the pharmaceutical composition.
 33. A pharmaceutical composition according to claim 1, wherein said composition is a solid pharmaceutical preparation in the form of a powder, granules, tablets, or pellets.
 34. A pharmaceutical composition according to claim 1, wherein the lipolytic activity of the enzymes or enzyme mixtures is provided by a microbial lipase.
 35. A pharmaceutical composition according to claim 1, wherein the microbial lipase is a bacterial or fungal lipase.
 36. A pharmaceutical composition according to claim 1, wherein the enzymes or enzyme mixtures also have proteolytic or amylolytic activity.
 37. A pharmaceutical composition according to claim 36, wherein the enzymes or enzyme mixtures comprise pancreatin.
 38. A pharmaceutical composition according to claim 36, wherein the enzyme mixture is a pancreatin-containing mixture of digestive enzymes.
 39. A pharmaceutical composition according to claim 36, wherein the pancreatin or pancreatin-containing mixture of digestive enzymes makes up 65-85% of the pharmaceutical composition.
 40. A pharmaceutical composition according to claim 39, wherein the pancreatin or pancreatin-containing mixture of digestive enzymes makes up 75-80% by weight of the pharmaceutical composition.
 41. A pharmaceutical composition according to claim 36, wherein the enzyme mixture comprises a mixture of at least one microbial lipase and at least one microbial enzyme selected from the group consisting of proteases and amylases.
 42. A pharmaceutical composition according to claim 41, wherein microbial enzymes make up 5-80% by weight of the pharmaceutical composition.
 43. A pharmaceutical composition according to claim 42, wherein microbial enzymes make up 20-60% by weight of the pharmaceutical composition.
 44. A pharmaceutical composition according to claim 36, wherein the enzyme or enzyme mixture is pancreatin or a pancreatin-containing mixture of digestive enzymes, additionally containing at least one microbial enzyme selected from the group consisting of lipases, proteases and amylases.
 45. A pharmaceutical composition according to claim 34, wherein the microbial lipase is a recombinantly produced fungal or bacterial lipase.
 46. A pharmaceutical composition according to claim 34, wherein the lipase is a lipase variant or a mutated lipase.
 47. A method of stabilizing the lipolytic activity of a lypolytically active solid enzyme composition under acid pH conditions, said method comprising incorporating in said composition a stabilizing system comprising at least one surfactant, at least one co-surfactant, and optionally a lipophilic phase.
 48. A method according to claim 47, wherein said composition comprises pancreatin or a pancreatin-containing mixture of digestive enzymes.
 49. A process for preparing a solid pharmaceutical preparation containing an enzyme or enzyme mixture with lipolytic activity, said process comprising converting the enzymes or enzyme mixture into a suitable medicament form with a system comprising a surfactant selected from the group consisting of polyethylene glycol fatty acid esters; polyethylene glycol glycerol fatty acid esters; polyethylene glycol alkyl ethers, polyethylene glycol sterol ethers, polyethylene glycol sorbitan fatty acid esters, sugar esters, polyoxyethylene-polyoxypropylene block copolymers, ionic surfactants and mixtures thereof; a co-surfactant selected from the group consisting of mono-acylglycerides, mono-ethers of glycerol, partial esters of propylenglycol, partial esters of polyglycerol, partial esters of ethyl diglycol and mixtures thereof, and a lipophilic phase represented by di- and/or triacylglycerides.
 50. A process according to claim 49, wherein said system further comprises at least one pharmaceutically compatible auxiliary, carrier or excipient. 